A large-sized dump truck working in mines and the like has been typically known. As a steering mechanism of front wheels (steering wheels) of such a dump truck, there has been typically known a steering mechanism including a yoke that is a part of a suspension and has a up-and-down movable proximal end supported on a vehicle body frame, a receiving seat rotatably attached to a distal end of the yoke, a knuckle arm attached to the receiving seat, and a steering cylinder extending between the knuckle arm and the vehicle body frame to connect the knuckle arm and the vehicle body frame (for instance, Patent Literature 1).
Moreover, an off-road dump truck has also been known for having steering wheels as all the tires in order to improve delivery performance (for instance, Patent Literatures 2 and 3).